• 대한치과보철학회지
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• 제40권5호
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• pp.451-469
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• 2002

The purpose of this study was to estimate the effect of a bleaching agent on tooth surfaces and to evaluate the resin bond strength according to different surface treatments on bleached teeth. To prepare for the experimental samples, first, extracted human third molars were used and the body portions of the crowns were cut into four equal-sized specimens. Next, each specimen was mounted in an plastic bottle with self-cured resin and highly polished to have them reveal the enamel or dentin surfaces. Then, the enamel(E) and dentin(D) specimens were divided into four ; 1) non-bleached, laser-treated(NBLA) group 2) bleached, laser-treated(BLLA) group 3) non-bleached, acid-treated(NBAC) group and 4) bleached, acid-treated(BLAC) group. Here, $opalescence^{(R)}$ (10% carbamide peroxide) was used for bleaching agent. The treated specimens were observed by confocal laser scanning microscopy and bonded with composite resin for shear bond test. The following results were obtained from this experiment : 1. Compared with the ENB group, the EBL group was shown be dyed about $20{\mu}m$ deeper with rhodamine B. The DBL group appeared to be caved in at the entry part of the dentinal tubules, was dyed about $20{\mu}m$ deeper and $5{\mu}m$ wider in diameter, compared with the DNB group. 2. In comparison with the EBLAC group, the ENBAC group looked evenly bonded with the resin, while the DNBAC group, compared to DBLAC group, was observed to have its resin tags penetrated about $50{\mu}m$ deeper. Other than those, however, no observable differences between ENBLA and EBLLA group or between DNBLA and DBLLA group were found. 3, At the shear bond test, the ENBAC group was shown to have statistically significant higher shear bond strength than the EBLAC group(p<0.05). No statistically significant differences between the ENBLA and the EBLLA groups were observed(p>0.05). 4. At the shear bond test, the DNBAC group was shown to have statistically significant higher shear bond strength than the DBLAC group(p<0.05). No statistically significant differences between the DNBLA and the DBLLA groups were observed(p>0.05). The in vitro observations above suggest that tooth-bleaching procedure brings a certain change on enamel and dentin surfaces and it weakens the shear bond strength with composite resin when the bleached tooth was acid-treated.

• Restorative Dentistry and Endodontics
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• 제30권3호
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• pp.178-183
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• 2005

본 연구에서는 현재 임상에서 home bleaching을 위해 사용되고 있는 표백 재료들이 치아 법랑질의 투명도에 어떠한 변화를 일으키는지 고찰해 보고자 시행하였다. 실험 대상으로는 하루 전 발거한 우치 (bovine tooth)를 사용하였다. 치아의 순면에 수직되게 다이아몬드 드릴을 이용해 수주 하에서 직경 6 mm의 원통형 치아 시편을 만들어 순면이 노출된 상태로 투명한 아크릭 레진에 포매한 후, low speed diamond saw (Isomat, Buehler Co., USA)를 사용하여 1.2 mm 두께로 절단하였다. 절단된 시편은 순면을 먼저 편평하게 연마하고,절단된 면을 연마하여 두께 1 mm의 시편을 완성하였다. 완성된 시편(우치 25개)을 무작위로 추출하여 3개의 그룹으로 나누고 나머지는 대조군으로 하였다. Opalescence$^{(R)} (10% carbamide peroxide, Ultradent, Milford, USA), Rembrandt$^{(R)} (10% carbamide peroxide, DenMat, USA) 및 Opalescence$^{(R)} F(15% carbamide peroxide with fluoride, Ultradent)를 시편의 순면에 1주일 동안 적용 (표백제는 24시간마다 교체)하였고, 설측면은 증류수를 적신 거즈에 접촉된 상태로 보관하였다 표백제를 적용하기 전과 적용 3, 5, 7일째에 시편의 삼자극치 X, Y, Z 값을 색채색차계 (Color & Color Differencemeter, Model TC-6FX, Tokyo Denshoku Co., Japan)로 백색 배경판과 흑색 배경판 상에서 측정하였다 백색 배경판과 흑색 배경판 상에서 측정된 Y값의 평균값을 이용해 contrast ratio를 계산하였다 얻어진 값을 One Way Repeated Measured ANOVA를 이용하여 통계 처리한 결과 10% Opalescence$^{(R)}처치군, 15% Opalescence$^{(R)}-F처치군 및 대조군에서는 통계적으로 유의할만한 증감을 보이지 않았고, Rembrandt$^{(R)}처치군에서는 Contrast ratio가 증가하였다 (p < 0.01).

• Journal of Oral Medicine and Pain
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• 제30권2호
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• pp.269-276
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• 2005

재래의 고속핸드피스 bur를 이용한 와동 형성시 레진 접착력과 레이저를 사용한 와동형성시 접착력을 비교하여 레이저의 임상적용 여부를 평가하는 것이 본 연구의 목적이다. 총 96개 치아 표본의 법랑질 협면과 상아질 mid-coronal 부에 Er:YAG laser를 사용하여 조사하였다. 사전에 산부식을 시킨 군(48개)과 부식시키지 않은 군(48개)으로 구별하고 각각 flowable 접착시스템(Metafil Flo)과 자가중합 시스템(Clearfil FII New Bond)를 레진에 접착시켰다. 37$^{\circ}C$ 증류수에서 24시간동안 보관한 후 미세 결합강도(micro-tensile shear strength)를 만능시험기(universal testing machine)로 측정하여 다음과 같은 결과를 얻었다. 1. 법랑질과 상아질 모두 산부식 전처리를 한 경우에 산처리를 하지 않은 경우보다 결합강도가 높았고, 레이저 처리 표본에서도 마찬가지여서 레이저만으로 처리하는 것보다는 산부식 처리를 하는 것이 강도면에서 유리한 것으로 나타났다. 2. 법랑질의 경우 레이저 처치한 경우가 bur로 삭제한 경우보다 두 레진군 모두에서 결합강도가 낮았으나(P<0.05), 상아질의 경우에는 flowable 레진군에서는 두 군 간의 차이가 없었다. 3. 레이저 처치군내에서 상아질의 경우, 광중합 flowable 레진의 결합강도가 자가중합형 레진의 강도보다 높았으나, 법랑질에서는 차이가 없었다. 따라서 레이저를 활용하여 와동을 형성하는 것은 상아질까지 확대된 와동의 경우에 법랑질에 국한된 경우보다 결합강도면에서 유리하며, flowable레진을 사용하는 것이 자가중합형 레진보다 유리한 것으로 판단되었다.

• 대한치과보존학회:학술대회논문집
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• 대한치과보존학회 2001년도 추계학술대회(제116회) 및 13회 Workshop 제3회 한ㆍ일 치과보존학회 공동학술대회 초록집
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• pp.586.1-586
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• 2001

Large butt-joint box typed class II cavites with cervical margins 1mm below the cemento-enamel junction were cut into 70 extracted human molars. The cavities(7 groups, n=10) were filled using a closed/open sandwich restoration or total bond restoration technique with materials according to the manufacturer's recommandation using the single-component bonding agent for each system. Teeth were thermocycled 500 times between $5^{\circ}C$ and $55^{\circ}C$ with 30-second dwell times.(omitted)

• 대한치과보존학회:학술대회논문집
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• 대한치과보존학회 2003년도 제120회 추계학술대회 제 5차 한ㆍ일 치과보존학회 공동학술대회
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• pp.573-573
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• 2003

I. Objective This study evaluated the microshear bond strength of teeth bleached with commercial whitening strips and compared with those bleached with home bleaching gel. II. Materials and Methods Twelve exrtacted central incisors were cut into pieces and central four segments were chosen from each tooth and embedded in acrylic resin. Four blocks with 12 tooth segments embedded in acrylic resin were acquired and numbered from one to four. Block 1 was bleached with Crest Whitestrips, block 2 with Claren, block 3 with Opalescence tooth whitening gel(10% carbamide peroxide).(omitted)

• Restorative Dentistry and Endodontics
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• 제28권3호
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• pp.203-208
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• 2003

The purpose of this study was to evaluate the effect of salivary contamination of teeth on bonding efficacy of self-priming and self-etching DBSs. The materials used were Single Bond(SB, self-priming system, 3M), Unifil Bond(UB, self-etching system, GC), and Scotchbond Multi-Purpose Plus(SM, 3M) as control. Forty five human molars randomly allocated to three groups as dentin bonding systems tested and embedded in epoxy resin. Then the specimens were wet-ground to expose flat buccal enamel surface or flat occlusal dentin surface and cut bucco-lingually to form two halves with slow speed diamond saw. One of them was used under non-contamination, other under contamination with saliva. The bonding procedure was according to the manufacturer's directions and resin composite(Z-100, 3M Dental Products, St. Paul, MN) was built-up on the bonded surface 5mm high. The specimens were ground carefully at the enamel-composite interface with fine finishing round diamond bur to create an hour-glass shape yielding bonded surface areas of $1.5{\pm}0.1\textrm{mm}^2$. The specimens were bonded to the modified microtensile testing apparatus with cyanoacrylate, attached to the universal testing machine and stressed in tension at a CHS of 1mm/min. The tensile force at failure was recorded and converted to a tensile stress(MPa). Mean values and standard deviations of the bond strength are listed in table. One-way ANOVA was used to determine significant difference at the 95% level. The bond strength of SBMP and SB were not affected by salivary contamination, but that of UB was significantly affected by salivary contamination. These results indicate that DBSs with total etch technique seems less likely affected by salivary contamination in bonding procedure.

• Restorative Dentistry and Endodontics
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• 제21권2호
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• pp.489-504
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• 1996

The purpose of this study was to compare the adaptation to the tooth structure of five light cured glass ionomer cements (Fuji II LC. VariGlass VLC, Vitremer, Dyract and Geristore). Human, non-carious fifty extracted permanent premolars stored in normal saline were used. Class V cavity preparations were created on the buccal surfaces. The occlusal margin of each cavity was placed on the enamel and the gingival margin was placed on the cementum/dentin. The teeth were then distributed at random into five groups of 10 teeth each. Group 1: Fuji II LC, Group 2 : VariGlass VLC, Group 3 : Vitremer, Group 4: Dyract, Group 5 : Geristore. The prepared cavities were restored with one of the five light cured glass ionomer cements. The manipulation of each material was handled according to the manufacturer's instructions. All samples were placed in incubator of 100% relative humidity at $37^{\circ}C$ for 24 hours. The roots of the teeth were removed with the tapered fissure bur and the remaining crowns were sectioned buccolingually through the center of restorations. The cut interfaces were gradually hand polished on sandpapers from 300 up to 1200 grit. The adaptation at the tooth/cements interface was assessed by SEM (JSM-840A, JEOL Ltd.). The results of this study were as follows : 1. Group 2 revealed the best adaptation and groups 1, 4 and 5 revealed similar adaptation pattern to the cavity walls. Group 3 revealed the worst adaptation to the cavity walls. 2. Enamel margins showed better adaptation than dentin/cementum margins with each material except group 3. 3. The hybrid layers were observed between the glass ionomer cement and dentin in groups 2, 4 and 5.

• 대한치과보철학회지
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• 제17권1호
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• pp.23-34
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• 1979

In this study, the adhesive strength of three commercial polycarboxylate cements to ten types of dental casting alloys, such as gold, palladium, silver, indium, copper, nickel, chromium, and human enamel and dentine were measured and compared with that of a conventional zinc phosphate cement. The $8.0mm{\times}3.0mm$ cylindrical alloy specimens were made by casting. The enamel specimens were prepared from the labial surface of human upper incisor, and the dentine specimens were prepared from the occulusal surface of the human molar respectively. Sound extracted human teeth, which had been kept in a fresh condition since, extraction, were mounted in a wax box with a cold-curing acrylic resin to expose the flattened area. The mounted teeth were then placed in a Specimen Cutter (Technicut) and were cut down under a water spray, and then the flat area on the all specimens were ground by hand with 400 and 600 grit wet silicone carbide paper. Two such specimens were then cemented together face-to-face with freshly mixed cement, and moderate finger pressure was applied to squeeze the cement to a thin and uniform film. All cemented specimens were then kept in a thermostatic humidor cabinet regulated at $23{\pm}2^{\circ}C.$ and more than 95 per cent relative humidity and tested after 24 hours and 1 week. Link chain was attached to each alloy specimen to reduce the rigidity of the jig assembly, and then all the specimens were mounted in the grips of the Instron Universal Testing Machine, and a tensile load was delivered to the adhering surface at a cross head speed of 0.20 mm/min. The loads to which the specimens were subjected were recorded on a chart moving at 0.50 mm/min. The adhesive strength was determined by measuring the load when the specimen separated from the cement block and by dividing the load by the area. The test was performed in a room at $23{\pm}2^{\circ}C.$ and $50{\pm}10$ per cent relative humidity. A minimum of five specimens were tested each material and those which deviated more than 15 per cent from the mean were discarded and new specimens prepared. From the experiments, the following results were obtained. 1) It was found that the adhesive strength of the polycarboxylate cement to all alloys tested was considerably greater than that of the zinc phosphate cement. 2) The adhesive strength of the polycarboxylate cements was superior to the non precious alloys, such as the copper, indium, nickel and chromium alloys, but it was inferior to the precious gold, silver and palladium alloys. 3) Surface treatment of the alloy was found to be an important factor in achieving adhesion. It appears that a polycarboxylate cement will adhere better to a smooth surface than to a rough one. This contrasts with zinc phosphate cements, where a rough helps mechanical interlocking. 4) The adhesion of the polycarboxylate cement with enamel was found superior to its adhesion with dentine.

• Restorative Dentistry and Endodontics
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• 제13권1호
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• pp.123-129
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• 1988

The purpose of this study was to evaluate the bond strength of glassionomer cement against cut dentin surface which was treated with various surface cleaning agents. 48 freshly extracted human 3rd molars were ground flat through the enamel into the dentin using 600 grit silicone carbide paper under a flow of water. The were divided into four groups by the following cleaning procedure on cut dentin surface; Group I : No surface treatment after grinding with 600 grit silicone carbide paper as control group Group II : Surface treatment with 50% citric acid for 30 seconds. Group III : Surface treatment with 37% phosphoric acid for 30 seconds. Group IV : Surface treatment with 10% poly acrylic acid for 30 seconds. The specimens in 4 groups were immersed in distilled water at $37^{\circ}C$ for 24 hours before testing after cleanising with water-spray and drying with air. Bond strength was measured with Instron Universal Testing Machine (Autograph S-100, Shimadzu, Kyoto, JAPAN). The results were as follows: 1. The bond strengths of group II, III & IV were not seemed to be shown more significant improvement than a group I. 2. The bond strengths in groups which were treated with 50% citric acid, 37% phosphoric acid and 10% polycrylic acid, were ranked 24.70kg/$cm^2$, 22.02kg/$cm^2$ and 31.13kg/$cm^2$, but its difference was not significant, statistically.

• Restorative Dentistry and Endodontics
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• 제26권4호
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• pp.263-272
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• 2001

저광도 중합법, 펄스 지연 중합법, 초고광도 중합법 등의 광조사 방식이 광중합형 복합레진 수복물에서의 중합수축 응력에 미치는 영향을 알아보기 위해 in vitro에서 미세 누출 실험을 하였다. 80개의 발거된 소구치의 협측면에 5급 와동을 형성하고, 600mW/$cm^2$로 30초간 광조사하는 보통 광도 중합군, 300mW/$cm^2$로 60초간 광조사하는 저광도 중합군, 400mW/$cm^2$로 2초간 광조사하고 5분간 기다린 후 800mW/$cm^2$로 10초간 최종 중합시키는 펄스-지연 중합군, 그리고 1930mW/$cm^2$의 광도로 3초간 광조사하는 초고광도 중합군 등의 4개의 군으로 나누어 hybrid 형의 광중합복합레진을 충전하고 각 군의 방법대로 중합한 후, 변연의 0.5mm 외부에 nail varnish를 도포하고 37$^{\circ}C$, 2% metylene blue 용액에 24시간 동안 침적시켰다. 시편을 아크릴릭 레진에 매몰한 후 수복물의 중앙에서 종절단하여 입체현미경하에서 그 단면을 관찰한 후 법랑질과 상아질 변연으로 나누어 색소의 침투도를 측정하여 다음과 같은 결과를 얻었다. 1. 펄스 지연 중합군의 색소 침투도는 법랑질과 상아질 변연 모두에서 보통광도, 저광도 및 초고광도 중합군과 유의한 차이를 보이지 않았다(p>0.05). 2. 상아질 변연에서 초고광도 중합군은 보통광도 중합군과 저광도 중합군에 비해 유의하게 높은 색소 침투도를 보였다(p<0.05). 3. 법랑질 변연에서의 4개 군의 색소 침투도는 서로 유의한 차이를 보이지 않았다(p>0.05). 4. 모든 군에서 상아질 변연에서의 색소 침투도는 법랑질군에서의 색소 침투도에 비해 유의하게 높았다(p<0.05).